A pedometer is a portable, electronic or electromechanical device that counts each step a person takes by detecting a person’s motion at the hips (Tudor-Locke et al, 2008). Originally, pedometers were used by athletes and fitness enthusiasts, but their use has now been extended to the larger population to help motivate people to reach their physical activity goals (Tudor-Locke et al, 2008). Pedometers are also an effective way for researchers to measure physical activity in free-living population while avoiding recall bias (Tudor-Locke, 2002). Pedometers are often worn on an individual’s belt loop and can be worn all day, in order to give a reading of how many steps the individual has walked that day. On some models, the individual can input their stride length into the system’s algorithm and the total distance walked can be calculated (Tudor-Locke, 2002). Step counters are being incorporated into portable electronic devices such as music players, smart phones, and mobile phones.

Contents

Definition

According to the Merriam Webster Dictionary, a pedometer is an instrument that records the distance a person covers on foot by responding to the body motion at each step. It is usually worn at the hip, although some models are designed to wear at the ankle. Pedometers differ from accelerometers in that accelerometers can also measure intensity, since they sense a change in acceleration.

History

The invention of the pedometer is commonly attributed to United States of America President Thomas Jefferson, however drawings from the fifteenth century indicate that Leonardo da Vinci invented the concept (Gibbs-Smith, 1978). Da Vinci’s early design was driven by gears and a pendulum that moved back and forth during the swing phase of walking (Tudor-Locke, 2002). The current use of pedometers is to assess physical activity and motivate walking behaviours (Hatano, 1993). This idea began in Japan over fifty years ago (Tudor-Locke, 2002). The first Japanese pedometer was available under the name “manpo-meter”, meaning “10,000 steps” in Japanese (Tudor-Locke, 2002). The manpo-meter was a huge success in Japan, as more than 90% of participants at walking events in Japan had been aware of the product for over five years and each household reported owning almost two pedometers (Tudor-Locke, 2002). Early research studies used mechanical pedometers, but these were subject to large error, making them unsuitable as research instruments (Tudor-Locke, 2002).

Uses

Pedometers are generally used as a motivational device for people who wish to increase their physical activity to achieve a healthier lifestyle. Individuals are able to log their progress using websites or smart phone applications or using a calendar. Clinical studies have demonstrated the effectiveness of pedometers in increasing physical activity and subsequently decreasing blood pressure, body mass index, and risks for multiple diseases (Bravata, 2007). Although daily targets should be specific to the individual, in 2004, the US Surgeon General recommended a daily target of 10,000 steps (Tudor-Locke & Bassett, 2004). While this recommendation may be effective for the average, ambulatory individual, it is subject to much criticism. A universal target such as the recommendation of 10,000 steps per day may be unsuitable for older populations, individuals with mobility issues, and those with chronic diseases or disorders. Additionally, pedometers are unable to record intensity of exercise, so in order to incorporate intensity into an individual’s fitness plan, a time constraint would have to be put in place.

There is increasing amounts of evidence to demonstrate that pedometers are practical, accurate, and acceptable tools for measurement of physical activity as well as for motivation (Tudor-Locke, 2002).

Benefits

The government of Canada recommends individuals complete at least 150 minutes of moderate to vigorous intensity physical activity per week for adults aged 18-64 (CSEP, 2014). By adhering to these recommendations, individuals can reduce their risk of premature death, chronic diseases such as coronary artery disease, stroke, hypertension, colon cancer, breast cancer, type two diabetes and osteoporosis (PHAC, 2014). Moderate-intensity walking is approximately equal to at least 100 steps per minute, so to meet the current guidelines, individuals should walk a minimum of 3000 steps in 30 minutes, 5 days per week (Marshall et al, 2009). Three bouts of 1000 steps in 10 minutes each would also suffice to meet the guidelines (Marshall et al, 2009).

In 2004, a Canadian study called “Health benefits of a pedometer-based physical activity intervention in sedentary workers” (Chan et al, 2004) concluded that physical activity in sedentary populations was increased through the use of a pedometer-based step program. This study also noted that individuals with a higher BMI at baseline achieved relatively similar increases in their physical activity as those whose BMI were lower (Chan et al, 2004).

If the step goals are personalized to the individual, considering baseline values, specific health goals and sustainability of that goal in everyday living, pedometers may be of practical importance for combating obesity (Tudor-Locke, 2002).

Uses for Children

Research evidence has demonstrated that children who are physically active are more likely to experience benefits to their physical, psychological and social health (Cox et al, 2005). Many studies have been subjected to recall bias when using self-report methods to monitor how much physical activity children are engaging in (Cox et al, 2005). Pedometry is an excellent way to monitor physical activity in a way that avoids recall bias and is non-invasive. Pedometry is widely used to study physical activity in children at school, in order to determine if physical activity programs should be modified to meet the needs of the children. Children require more physical activity per day than adults, and thus the daily recommendations should be adjusted to reflect that. Results from pedometer studies in children indicate that it is recommended that children walk 11,000 steps per day for girls and 13,000 steps per day for boys at least five days a week to prevent or decrease overweight and obesity in youth (Tudor-Locket & Bassett, 2004).

Technology

The pedometer has a simple design and requires no additional software to interpret data (Tudor-Locke, 2002). Internally, a pedometer consists of a horizontal, spring suspended lever arm that moves up and down during normal ambulation (Tudor-Locke, 2002). There is an electrical circuit that closes with each movement that is detected, allowing an accumulated step count to be displayed digitally (Tudor-Locke, 2002).

Accuracy

While pedometers can be a useful tool for measuring physical activity there are some sources of error to be noted. Some pedometers can mistake non-walking movements for steps the individual has taken. For example, bending over, bumps in the road while driving or sitting down and standing back up can me mistaken for steps since all of these actions cause a change in the person’s hip acceleration.

The accuracy of pedometers varies between devices. Pedometers are most accurate when the individual is on level ground and moving at a walking pace. The most efficient pedometers are accurate to ± 5% error (Vincent & Sidman, 2003).